%计算在邻居单元对应点的基函数的值
function b_edge_value = neighbor_edge_value(tri, cell)
b1 = @(x,y) 1 - 2.*x;
b2 = @(x,y) 2.*x + 2.*y -1;
b3 = @(x,y) 1 - 2.*y;
b_edge_value = zeros(3,4,3);
for i = 1 : 3
    for j = 1 : 4
        node = tri(cell).neighbor_rf(j,:,i);
        b_edge_value(1,j,i) = b1(node(1),node(2));
        b_edge_value(2,j,i) = b2(node(1),node(2));
        b_edge_value(3,j,i) = b3(node(1),node(2));
    end
end
end